The invention relates to an apparatus for measuring the warp tension as well as to a weaving machine or loom having an apparatus of this kind.
An apparatus arranged on the breast beam for measuring the warp tension is known from CH-B 556 416 which is actuated by a force exerted by the running fabric.
A measurement device is described in EP-A 0 385 061 comprising a tube having a radially extending groove, a measurement beam arranged in the groove, a carrier arranged underneath the measurement beam and secured in the tube and two measurement value sensors for measuring the fabric tension, which is proportional to the warp yarn tension.
In this measurement device strain gauges are arranged on members which connect the carrier and the measurement beam and transmit a signal which corresponds to the bending deflection of the members.
The strain gauges are subjected to oscillations which are caused by the warps running over the measurement beam or by the weaving machine or loom. Such superimposed oscillations cannot be overcome by technical circuit measures and thus considerably falsify the measurement result, i.e. a dynamic warp tension measurement cannot be carried out. In another embodiment, pressure pick-ups are used which are arranged between the lower side of the measurement beam and the associated upper side of the carrier, so that the measurement beam lies freely on the pressure pick-ups.
In this embodiment, oscillations likewise beam arise and, moreover, during a change in running of the fabric, a tilting movement of the measurement beam arises within the cut-out which leads to a non-uniform force distribution. Furthermore, the installed length is restricted to a perpendicular arrangement of the measurement beam.